X-Linked Hydrocephalus: L1CAM Sequencing

Turnaround Time

6 weeks

CPT Code(s)

81407

Cost

$1,500

Genes

• X-Linked Hydrocephalus

L1CAM is associated with a phenotype spectrum including X-linked hydrocephalus, MASA (intellectual disability, aphasia, spastic paraplegia and adducted thumbs), X-linked complicated hereditary spastic paraplegia type 1 (SPG1) and X-linked agenesis of the corpus callosum. The gene encodes for neuronal L1 cell adhesion molecules in the central and peripheral nervous systems, and has been localized to Xq28.

Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.

Sanger Sequencing

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA, dried blood spots, and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Prenatal diagnosis is available if the familial mutation is known. Prenatal diagnosis can also be requested when there are ultrasound findings suggestive of an L1CAM mutation. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests Contact the laboratory prior to sending a prenatal specimen.